Complex formed to separate 3,5-xylenol or 3,4-xylenol from other polymethylated phenolic compounds

ABSTRACT

A process is disclosed for separating 3,5-xylenol or 3,4-xylenol from other closely boiling polymethylated phenolics by treating a mixture of the phenolics with a metal halide salt. The metal halide salt preferentially forms a complex with the xylenol over other related phenolics in the mixture. The preferentially-formed complex of the xylenol may then be isolated from the mixture and the complex decomposed to provide a product substantially enriched in, or substantially entirely composed of the xylenol.

This is a continuation of application Ser. No. 431,651, filed Sept. 30,1984, U.S. Pat. No. 4,447,658.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Preferential complexation of one organic compound in a mixture ofrelated compounds is a known technique for resolving mixtures of closelyrelated compounds. Of particular interest herein are methods forisolating 3,5-xylenol and/or 3,4 xylenol from close boiling mixtures, bypreferential complexation of one of the phenolics.

2. Description of the Prior Art

Mixtures of polymethyl phenolics are available as by-products from thecoking of coal and the base extraction of petroleum fractions. Theisolation and purification of individual phenolics is very difficult bythe use of conventional separation methods such as fractionaldistillation and fractional crystallization. This fact may be seen fromthe table below which lists twelve phenols boiling within a 25° range.

    ______________________________________                                                        Boiling Point                                                                            Melting Point                                      Phenol          (°C.)                                                                             (°C.)                                       ______________________________________                                        2,3-xylenol     218        73                                                 3,5-xylenol     221        63                                                 3,4-xylenol     226        65                                                 2,5-xylenol     211        74                                                 2,4-xylenol     211        25                                                 2,3,6-trimethylphenol                                                                         220        62                                                 2,4,6-trimethylphenol                                                                         220        71                                                 2,3,4-trimethylphenol                                                                         237        81                                                 2,3,5-trimethylphenol                                                                         235        95                                                 2,4,5-trimethylphenol                                                                         236        72                                                 m-ethylphenol   218        -4                                                 p-ethylphenol   219        46                                                 ______________________________________                                    

There are chemical processes known for separating closely-relatedorganic compounds by methods other than, or in addition to,energy-intensive physical separation techniques such as fractionaldistillation or fractional crystallization. These chemical processesinvolve a step of preferential complexation of one component of amixture of closely-boiling compounds over other components of themixture. For example, U.S. Pat. No. 4,267,389 to Leston, describestreating a phenolic mixture comprising para-cresol, methylated phenolsand ethylated phenols with an inorganic halide salt, such as calciumbromide, to remove para-cresol from the mixture. Removal of para-cresolfrom the mixture involves formation of a complex between para-cresol andcalcium bromide, which complex forms preferentially over complexesbetween calcium bromide and other components of the phenolic mixture.

Mixtures of various alcohols may be resolved by treatment with a halidesalt. For example, in Sharpless et al., J. Org. Chem., Vol. 40, No. 9,p.p. 1252-1257 (1975), there is reported a study of competition betweenpairs of mono-hydroxy alcohols and mono-hydroxy phenols for complexformation with a halide salt. This study finds that phenols as a classform poorer complexes than alcohols of comparable melting point,probably because the phenols are weaker bases than the comparablealcohols.

There remains need, therefore, for methods for resolution of mixtures ofclosely-related phenolics by chemical complexation methods, rather thanby fractional crystallization or distillation.

SUMMARY OF THE INVENTION

A mixture of two or more polymethyl phenolics may be resolved intoindividual phenolic components by a process involving a step of forminga solid complex preferentially between a metal halide salt and one ofthe phenolics in the mixture containing at least one phenolic from thegroup consisting of 3,5-xylenol and 3,4-xylenol. A metal halide saltsuitable for forming the solid complex may be selected from the groupconsisting of calcium bromide, calcium chloride, lithium bromide,magnesium chloride and magnesium bromide. Resolution of such a phenolicmixture may be accomplished by either of the following two preferredmethods.

A first method involves bringing together a mixture of two or morephenolics at least one of which is 3,5-xylenol or 3,4-xylenol, and aselected metal halide salt, the metal halide being selected such that acomplex forms with one of the above xylenols in preference to, orpreferentially over, other phenolics in the mixture. This preferentiallyformed complex constitutes a solid material in contact with a liquidphase such as may be provided by aliphatic, alicyclic and aromatichydrocarbons, and their chlorinated derivatives, ethers, esters andketones. Also, any combination of such solvents may be used. Alcoholsare specifically excluded as solvents inasmuch as they form complexeswith the metal halide salt solvent. The solid complex may then beremoved or isolated from the liquid phase and thereafter decomposed to aproduct comprising a predominantly greater amount of thepreferentially-complexed phenolic than other phenolics, as compared tothe relative amounts of phenolics present in the original mixture. Theproduct may also contain phenolic derived from complexes which form withthe selected metal halide salt, but in lesser amount than the amount ofphenolic derived from the preferentially-formed complex.

A second method involves forming a mixture of two or more phenolics, atleast one of which is either 3,5-xylenol or 3,4-xylenol, in contact witha selected metal halide salt, the metal halide salt initially present inan amount relative to one phenolic and selected such that one or morecomplexes form between the selected metal halide salt and one or more ofthe phenolics, but such that at least one of the phenolics forms nocomplex or forms a significantly lesser amount of complex with theselected metal halide salt than the preferentially-complexed phenolic.This phenolic which forms no complex, on which forms a complex in asignificantly lesser amount than other phenolics relative to amounts ofphenolics originally present in the mixture, remains dissolved in theliquid phase. The solvent providing the liquid phase may then be removedor isolated from the preferentially-complexed phenolics which arepresent as solid material. Removal of the solvent provides a productcontaining an enriched amount of the phenolic which did notpreferentially complex with the selected metal halide salt, as comparedto the original mixture of phenolics.

One advantage provided by the process of the invention is goodresolution or mutual separation of pairs of phenolics can be obtainedfrom a mixture of two or more phenolics which separation would besubstantially impossible to accomplish in a one-stage fractionaldistillation or crystallization. A second advantage resides in thischemical-separation process requiring significantly less energy toaccomplish good resolution of the phenolics than physical-separationmethods such as fractional distillation or crystallization.

The chemical-separation process of the invention may also be usedadvantageously in conjunction with conventional physical-separationprocesses. For example, calcium bromide complexation may be used in aninitial treatment of a phenolic mixture for separation two or morecompounds. Then, a resulting mixture of compounds having boiling pointsfurther apart can be treated by distillation or crystallization for morecomplete resolution of the mixture.

DETAILED DESCRIPTION OF THE INVENTION

The terms "phenol", "phenols", "phenolic" or "phenolics" as used hereinincludes xylenols; trimethylphenols and monoethylphenols. The phrases"resolving a mixture of phenolics" and "resolution of a mixture ofphenolics" relate to a mechanism or a result in which the individualphenolic components of a mixture containing two or more phenolics may beseparated or isolated from each other. Thus, the separation of asignificant amount of one phenolic from a mixture of two phenolicsconstitutes a resolution of the mixture. The phrases also embraceseparation of a multi-component mixture into groups of phenolics, eachgroup containing two or more phenolics. Also included within thedefinition are treatments resulting in a significant increase in theamount of one or more phenolics as compared to the composition of theoriginal mixture of phenolics, even where the original mixture containedrelatively small amounts of the enriched phenolic. It is contemplatedthat a differentation or enrichment in the relative amounts of phenolicsis a "significant enrichment" if treatment of a mixture provides anincrease of at least about 20 weight percent in one or more of thephenolics as compared to the composition of the original mixture.

The phrases "preferentially-formed complex" and "predominantly-complexedphenolic" are intended as abbreviated descriptions of the complexcomprising a selected metal halide salt and phenol which forms in anamount significantly greater than an amount of any other complex ofanother phenolic resulting from treatment of the phenolic mixture withthe selected metal halide salt. Any complex formed will preferably becomprised substantially entirely of a complex of a single type ofphenolic. It is recognized, however, that other phenolics in a startingmixture may form complexes with the selected salt in secondary or lesseramounts than the primary, predominantly-formed complex. Such secondarycomplex formation in lesser amounts is not deleterious provided that theratio of the predominant complex to the secondary complex in theresulting solid material is sufficiently high to provide a usefulresolution of a phenolic mixture. It is contemplated that aprimary/secondary or predominant/lesser ratio of the relative amounts ofcomplexes of the treated mixture constitutes a significant andusefully-resolved mixture of phenolics.

Mixtures of phenolics susceptible to treatment with the process of theinvention include mixtures of two or more phenolics boiling in the rangeof about 210° C. to about 238° C. Such phenolics include 2,3-, 2,4-,2,5-, 3,5- and 3,4-xylenols, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5- and 2,4,6-,trimethylphenols and m,p-ethylphenols.

The family of metal halide salts which may be used in the process of thepresent invention is characterized by several common properties. Forexample, in addition to each member of the family being an inorganicsalt of a metallic chloride or bromide, these halide salts arecharacterized in taking on water of hydration. The hydratable nature ofthese metal halide salts is believed to be significant in the mechanismof complex formation with the phenolics, even though no water isinvolved in the complexation reaction. Of the family of metal halidesalts suitable for use in the invention, calcium bromide is preferred.It is also preferred, whether calcium bromide or calcium chloride or anyother of the halide salts is used, that the salt have a water content,either as hydrate or occluded, of less than about ten weight percent.Also, it is preferred that the salt have a particle size less than about200 mesh.

Solvents which may be used in the complexation reaction include thoseorganic compounds which dissolve the phenolic mixtures but do notpreferentially react with the metal halide salt. Solvents suitableinclude aliphatic, alicyclic and aromatic hydrocarbons, theirchlorinated derivatives, ethers, esters and ketones. Alcohols arespecifically excluded since they may form complexes with the metalhalide salt. Mixtures of solvents may also be used.

The process of the invention is particularly suitable for resolvingmixtures of closely boiling phenolics, one of which is 3,5,- or3,4-xylenol. Examples of such mixtures include the following:3,5-xylenol and 2,3,6-trimethylphenol; 3,5-xylenol and2,4,6-trimethylphenol; 3,5-xylenol and 2,3-xylenol; 3,4-xylenol and2,3,6-trimethylphenol; 3,4,-xylenol and 2,4,6-trimethylphenol;3,4-xylenol and 2,3-xylenol and mixtures consisting of three of thesefive above mentioned components, at least one of which is 3,5-xylenol or3,4-xylenol. Generally, in a mixture containing 3,5-xylenol, the3,5-xylenol is preferentially complexed. Generally, in a mixturecontaining 3,4-xylenol, the 3,4-xylenol is preferentially complexed withcalcium bromide.

Generally, the metal halide salt is added to the mixture of phenolicsdissolved in, or in contact with, a solvent. For calcium bromide, forexample, the salt is preferably added in amount in a range from about0.1 mole to about 4 moles to one mole of the phenolic to bepreferentially complexed. Usually, the complexation reaction takes placein the presence of a catalyst such as a lower aliphatic alcohol. Atypical catalytic amount of the alcohol would be approximately five molepercent of the alcohol based on the total phenolic content.

After the aforementioned components are brought together as a mixture,usually in the form of a slurry, the mixture is agitated for a period oftime sufficient for the phenolic-metal halide salt complex to form. Atypical mixing time is in a range from about one hour to about 24 hours.Mixing is typically conducted at room temperature and at atmosphericpressure, although the complexation reaction may be conducted atpractically any temperature in a range from about 0° C. to about 150° C.Superatmospheric pressure may be used to avoid escape of reactants andsolvents. Also, care must be taken to exclude ambient moisture from thereaction mixture.

After the mixing period, the mixture contains a fluffy, white or graysolid material component in contact with a liquid component. The solidmaterial may be separated from the liquid component by any conventionalseparation techniques such as by decanting, by centrifugation, or byfiltration. If filtration is used to separate the solid material fromthe liquid, the filtration may be conducted with the aid of pressuregradient applied across the filter medium. The separated solid materialmay be washed with small portions of solvent, and the washingsthereafter may be combined with the filtrate. After the washing step,the separated solid material may be optionally dried, usually by meansof low heat or in a desiccator under reduced pressure. The drying stepis carried out until the solid material reaches a constant weight.

The solid material, which contains the phenolic-metal halide saltcomplex, is then decomposed to provide the desired phenolic.Decomposition may be accomplished by hydrolysis of the complex in water,by heating of the complex at a temperature usually in a range of fromabout 150° C. to about 350° C., or by treatment with an alcohol, such asa lower boiling aliphatic alcohol. Preferred decomposition methodsinclude water hydrolysis and heat treatment of the complex. Indecomposition of the complex by water hydrolysis, the phenolic may berecovered by treating the water with an organic solvent, typicallyether. In decomposition of the complex with heat, the phenolic may beseparated by filtration, centrifugation or distillation from the metalhalide salt residue. In either of these decomposition methods, the metalhalide salt may be recovered and recycled for treatment of anothermixture of phenolics, or for subsequent treatment of the separatedphenolics in the event of incomplete separation of the mixture ofphenolics.

It is an important feature of the invention that the liquid portion ofthe mixture treated with the metal halide salt contains the phenolicwhich less predominantly forms a complex with the metal halide salt orwhich forms substantially no complex with the metal halide salt. Thusthe liquid portion of the treated mixture will be enriched in thisphenolic and depleted in the phenolic which predominantly complexes withthe metal halide salt. This phenolic may be recovered from this liquidportion by conventional distillation or fractionation techniques.

In order to demonstrate the invention, a series of individualpolymethylated phenolics were treated with calcium bromide to show theformation of a phenolic-CaBr₂ complex, as described in Examples I to IX.

EXAMPLE I

A reaction vessel equipped with stirring means was charged with 3.05 g3,5-xylenol (25 mmole), 0.1 ml absolute ethanol and 25 ml hexane as asolvent for the organic components. To the reaction vessel was added 5.0g powdered anhydrous calcium bromide (25 mmole) to form a slurry-likemixture. The reaction vessel was equipped with a drying tube filled witha desiccant, such as anhydrous calcium sulfate, for the purpose ofexcluding atmospheric moisture from the reaction mixture during thereaction period. A complexation reaction was run by stirring thismixture for about 1.5 hours at room temperature, after which time 10 mlhexane was added. Thereafter, the mixture was stirred about 5 minutes.The mixture was observed to contain a large amount of fluffy, whitesolid material suspended in the liquid solution. The mixture wasfiltered under suction, in a manner to minimize exposure of the mixtureto ambient moisture, so as to separate the fluffy solid material fromthe liquid component. The separated solid material was washed with smallportions of hexane and the hexane washings were combined with thefiltrate. The washed solid material was dried in a desiccator under apressure of 1 mm Hg absolute for a period of time until a substantiallyconstant weight was recorded of 7.30 g. Inasmuch as the dried solidmaterial weighed 7.30 g, it was determined that 2.30 g 3,5-xylenol hadcomplexed with the calcium bromide.

EXAMPLE II

A complexation reaction was run generally as described in Example I witha mixture of 12.2 g 3,5-xylenol (100 mmole), 0.1 ml absolute ethanol,and 5.0 g powdered anhydrous calcium bromide (25 mmole) in some toluene.After the mixture was stirred for a total of 18 hours it was worked up.A washed-and-dried solid material was obtained in an amount of 8.75 g.The filtrate was concentrated on a steam bath to a constant weight of8.2 g. Inasmuch as 3.75 g 3,5-xylenol apparently complexed with 5.0 gCaBr₂, it was determined that the 3,5-xylenol/CaBr₂ molar ratio was1.2:1.0.

EXAMPLE III

A complexation reaction was run generally as described in Example I witha mixture of 6.1 g 3,4-xylenol (50 mmole), 0.1 ml absolute ethanol, 10.0g powdered anhydrous calcium bromide (50 mmole) and 25 ml of toluene.After the mixture was stirred for a total of 18 hours it was dilutedwith toluene. A washed-and-dried solid material was obtained in anamount of 14.9 g. The filtrate was concentrated on a steam bath to aconstant weight of 12.75 g. Inasmuch as 4.9 g 3,4-xylenol had apparentlycomplexed with 5.0 g CaBr₂, it was determined that the 3,4-xylenol/CaBr₂molar ratio was 0.61:1.0 in this complex.

EXAMPLE IV

A complexation reaction was run as generally described in Example IIIwith a starting mixture of 12.2 g 3,4-xylenol (100 mmole), 0.1 mlabsolute ethanol, 5.0 g powdered anhydrous calcium bromide (25 mmole)and some of toluene. After the mixture was stirred for a total of 18hours it was worked up. A washed-and-dried solid material was obtainedin an amount of 10.7 g for a 3,4-xylenol/CaBr₂ molar ratio of 1.9:1.0.

EXAMPLE V

A complexation reaction was run as generally described in Examples andIV with a mixture of 12.2 g 3,4-xylenol (100 mmole), 0.1 ml absoluteethanol, 10.0 g powdered anhydrous calcium bromide (50 mmole) and 50 mlof toluene. After the mixture was stirred for a total of 48 hours it wasworked up. A washed-and-dried solid material was obtained in an amountof 20.75 g. The filtrate left 3.9 g after removal of the solvent.Inasmuch as 10.75 g 3,4-xylenol had apparently complexed with 10.0 gCaBr₂, it was determined that the 3,4-xylenol/CaBr₂ molar ratio was1.8:1.0.

EXAMPLE VI

A complexation reaction was run as generally described in Example I witha mixture of 12.2 g 2,4-xylenol (100 mmole) and 20.0 g powderedanhydrous calcium bromide (100 mmole) in some of hexane. After themixture was stirred for five hours no complex seemed to have formedbecause the solid settled rapidly when stirring was stopped. Next, 0.1ml of ethanol was added and stirring was resumed. After 1.25 hours, themixture became thick and it was diluted with 50 ml hexane. Twice more 50ml of hexane had to be added. A washed-and-dried solid material wasobtained in an amount of 7.29 g. The filtrate was concentrated on asteam bath to a constant weight of 12.75 g. Inasmuch as 2.3 go-t-butylphenol apparently complexed with 5.0 g CaBr₂, it was determinedthat the 2,4-xylenol/CaBr₂ molar ratio was 0.61:1.0.

EXAMPLE VII

A mixture of 12.2 g (100 mmole) of 2,4-xylenol (Aldrich, 99%), 5.0 g (25mmole) calcium bromide, five drops of ethanol and 30 ml of toluene wasstirred magnetically for several hours but no complex formed. A smallamount of previously prepared calcium bromide/2,4-xylenol complex wasadded and stirring was continued overnight. The thick purple complex wasdiluted with solvent and filtered yielding 5.5 g of fine product and0.35 g of coarse product on drying. Assuming the coarse material to beunreacted calcium bromide, the phenol/salt molar ratio is 0.30; assumingit to be complex, the ratio is 0.28. The 2,4-xylenol recovered from thefiltrate amounted to 10.9 g.

EXAMPLE VIII

A solution of 12.2 g (100 mmoles) of 2,5-xylenol and ten drops ofethanol in 100 ml of toluene was stirred magnetically for 16 hours with5.0 g (25 mmoles) of calcium bromide which had been reacted withm-cresol and the m-cresol complex decomposed by heating to 200° underreduced pressure. The solid amounted to 6.85 g corresponding to a2,5-xylenol/calcium bromide molar ratio of 0.61. The filtrate left 10.3g after base extraction, acidification, crystallization, filtration anddrying.

EXAMPLE IX

A solution of 6.1 g (50 mmoles) of 2,3-xylenol and ten drops of ethanolin 60 ml of toluene was stirred with 2.5 g (12.5 mmoles) of"m-cresol-activated calcium bromide" for 22 hours. Them-cresol-activated CaBr₂ was prepared as described in Example VIII. Thesolid was worked up and amounted to 3.45 g. The filtrate, on extractionwith caustic, acidification, filtration and drying, gave 5.0 g. Thus themolar ratio of 2,3-xylenol to calcium bromide was 0.62. The presence of2,3-xylenol in the solid was further verified by GC analysis of theorganic extract of the hydrolyzed solid.

As shown in Examples X to XVII, various synthetic mixtures of phenolics,containing 3,5-xylenol or 3,4-xylenol were prepared for treatment withcalcium bromide to show the preferential complexation of one of theabove phenolic over another phenolic, so as to allow separation of twoor more phenolics. In the working examples which follow, theextracted-and-decomposed complexes of the separated solid material andthe liquid portions were subjected to GC or IR analysis to determine therelative amounts of the phenolics in the solid material and in theliquid filtrate.

EXAMPLE X

A solution containing 6.10 g (50.0 mmoles) of 3,5-xylenol, 6.10 g of2,3,6-trimethylphenol (95%) pure, and 0.1 ml ethanol in 50 ml of benzenewas stirred magnetically at room temperature with 10.00 g (50.0 mmoles)of dry, powdered CaBr₂. After three hours the mixture had become thickand 100 ml of benzene was added. After the weekend, the mixture wasagain thick and stirring had stopped. Stirring was restarted for 15minutes and then the solid was filtered by suction, washed with benzeneand dried in vacuo to a constant weight of 12.96 g. A sample of thesolid was decomposed by water-acetone mixture and by methanol andanalyzed by GC. Also analyzed were the original solution and thecombined filtrate and washings with the following results (in area %):

    ______________________________________                                        Sample 3,5-Xylenol 2,3,6-trimethylphenol                                                                         Unknown                                    ______________________________________                                        Feed   49.3, 49.2  48.0, 48.0      1.5, 1.5                                   Complex                                                                              95.5,.sup.(1) 98.5.sup.(2)                                                                2.0,.sup.(1) 1.3.sup.(2)                                                                      --                                         Filtrate                                                                             33.6        63.0            2.7                                        ______________________________________                                         .sup.(1) Decomposed by methanol.                                              .sup.(2) Decomposed by wateracetone.                                     

EXAMPLE XI

A solution of 6.1 g (50.0 mmoles) of 3,4-xylenol, 6.1 g,2,3,6-trimethylphenol (95% pure) and 0.1 ml ethanol in 150 ml ofbenezene was magnetically stirred with 10.00 g (50.0 mmoles) of dry,powdered CaBr₂. The stirring had stopped during the weekend and thesolid was filtered by suction, washed with benzene and dried in vacuo toa constant weight of 12.79 g. A sample of the solid was hydrolyzed inacetone-water and analyzed by GC as were the feed and the combinedfiltrate and washings with the following results (in area %):

    ______________________________________                                        Sample     3,4-Xylenol 2,3,6-Trimethylphenol                                  ______________________________________                                        Feed       41.7, 8.4   48.3, 50.6                                             Complex    97.7, 97.1  2.3,.sup.(1) 2.9.sup.(1)                               Filtrate   30.9        63.3                                                   ______________________________________                                         .sup.(1) includes impurities, possibly 2,3xylenol.                       

EXAMPLE XII

A solution of 3.05 g (50 mmoles) of 3,5-xylenol, 3.05 g2,4,6-trimethylphenol and 0.1 ml ethanol in 50 ml of benzene was stirredmagnetically with 5.00 g (25 mmoles) of dry powdered CaBr₂ in theabsence of moisture (drying tube). After 1.5 hours, another 40 ml ofbenzene was added. The mixture was too viscous to stir the followingmorning. The solid was filtered by suction, washed with benzene anddried to a constant weight of 5.39 g. A sample of the solid wasdecomposed in methanol and analyzed by GC. Also analyzed were thestarting solution and the combined filtrate and washings. The analyticalresults were as follows (in area %):

    ______________________________________                                        Sample     3,5-Xylenol                                                                             2,4,6-Trimethylphenol                                    ______________________________________                                        Feed       49.0, 49.0                                                                              51.0, 50.8                                               Solid      85.5, 85.8                                                                              14.5, 14.2                                               Filtrate   45.5, 45.5                                                                              54.5, 54.5                                               ______________________________________                                    

EXAMPLE XIII

A solution of 3.05 g (50 mmoles) of 3,4-xylenol, 3.05 g of2,4,6-trimethylphenol and 0.1 ml of ethanol in 50 ml of benzene wasstirred magnetically with 5.00 g (25 mmoles) of dry, powdered CaBr₂ inthe absence of moisture (drying tube). Two increments of 40 ml each ofbenzene were added during the first two hours to keep the mixturestirring. The following morning, the mixture was a gel and stirring hadstopped. The solid was filtered by suction, washed with benzene anddried in vacuo to a constant weight of 5.75 g. A sample of the solid wasdecomposed in methanol and analyzed by GC. Samples of the feed andcombined filtrate and washings were also analyzed with the followingresults (in area %).

    ______________________________________                                        Sample     3,5-Xylenol                                                                             2,4,6-Trimethylphenol                                    ______________________________________                                        Feed       49.5, 44.1                                                                              50.0, 55.5                                               Complex    98.2      0.6                                                      Filtrate   37.5, 34.2                                                                              62.0, 65.4                                               ______________________________________                                    

EXAMPLE XIV

A solution of each 3.05 (25.0 mmoles) of 3,5-xylenol, 2,3-xylenol and0.1 ml ethanol in 100 ml of toluene was stirred magnetically with 5.00 g(25.0 mmoles) of dry, powdered CaBr₂ in the absence of moisture (dryingtube). The following morning the solid was filtered by suction, washedwith toluene and dried in vacuo to a constant weight of 5.17 g. A sampleof the solid was decomposed in methanol and analyzed by GC. Samples ofthe original solution and the combined filtrate and washings were alsoanalyzed with the following results (in area %):

    ______________________________________                                        Sample        3,5-Xylenol  2,3-Xylenol                                        ______________________________________                                        Feed          48.4         51.6                                               Complex       ca. 99       trace                                              Filtrate      43.6, 40.6   56.4, 59.4                                         ______________________________________                                    

A sample of the solid was hydrolyzed in water and the mixture wasextracted twice with CS₂. IR of the extracts showed 3,5-xylenol with atrace of 2,3-isomer.

EXAMPLE XV

A solution of each 3.05 g (25.0 mmoles) of 3,4-xylenol and 2,3-xylenoland 0.1 ml of ethanol in 100 ml of toluene was stirred magnetically with5.00 g (25.0 mmoles) of dry powdered CaBr₂ in the absence of moisture(drying tube). The following morning the stirring had stopped becausethe mixture had become thick. The solid was filtered by suction, washedwith toluene and dried in vacuo to a constant weight of 6.45 g. A sampleof the solid was decomposed in methanol and analyzed by GC. Samples ofthe original solution and the combined filtrate and washings were alsoanalyzed with the following results (in area %):

    ______________________________________                                        Sample        2,3-Xylenol                                                                             3,4-Xylenol                                           ______________________________________                                        Feed          52        48                                                    Complex        9        91                                                    Filtrate      65        35                                                    ______________________________________                                    

EXAMPLE XVI

A solution of 1.50 g of each 3,5-xylenol, 2,3-xylenol,2,3,6-trimethylphenol and 2,4,6-trimethylphenol and 0.1 ml ethanol in 50ml of toluene was stirred magnetically with 5.00 g of dry, powderedCaBr₂ in the absence of moisture (drying tube). On the followingmorning, the solid was filtered by suction, washed with toluene anddried in vacuo to a constant weight of 5.10 g. A sample of the solid wasdecomposed in methanol and analyzed by GC. Samples of the originalsolution and the combined filtrate and washings were also analyzed by GCwith the following results (in area %):

    ______________________________________                                                 Xylenols    Trimethylphenols                                         Sample     3,5-   2,3-       2,4,6-                                                                             2,3,6-                                      ______________________________________                                        Feed       22     27         24   27                                          Complex    100     0          0    0                                          Filtrate   21     28         24   27                                          ______________________________________                                    

A sample of the solid was hydrolyzed in water and the mixture wasextracted twice with CS₂. The phenolic component of the extract wasidentified as 3,5-xylenol by IR.

EXAMPLE XVII

A solution of 1.50 g of each 3,4-xylenol, 2,3-xylenol,2,3,6-trimethylphenol and 2,4,5-trimethylphenol and 0.1 ml ethanol in 50ml of toluene was stirred magnetically with 5.00 g of dry powdered CaBr₂in the absence of moisture (drying tube). The following morning themixture was very thick and barely stirring. The solid was filtered bysuction, washed with toluene and dried in vacuo to a constant weight of5.56 g. A sample of the solid was decomposed in methanol and analyzed byGC. Samples of the original solution and the combined filtrate andwashings were also analyzed by GC with the following results (in area%).sup.(1) :

    ______________________________________                                                 Xylenol     Trimethylphenol                                          Sample     2,3-   3,4-       2,4,6-                                                                             2,3,6-                                      ______________________________________                                        Feed       25.0   20.8       28.7 25.4                                        Complex     3.8   92.1       0     4.1                                        Filtrate   26.8   14.5       31.2 27.6                                        ______________________________________                                         (1) All are averages of two determinations.                              

EXAMPLE XVIII

A sample of tar acid gave the following GC analyses:

    ______________________________________                                        Component        Area Percent                                                 ______________________________________                                        o-Cresol         0.03                                                         m,p-Cresol       1.08                                                         2,4-2,5-Xylenol  14.74                                                        3,5-Xylenol      72.20                                                        3,4-Xylenol group                                                                              --                                                           2,3,5-Trimethylphenol                                                                          11.95                                                        ______________________________________                                    

A solution of this tar acid, 17.5 g (corresponding to 0.10 mmole of3,5-xylenol at 70% concentration), in 50 ml of hexane and 20.0 g ofanhydrous ball-milled calcium bromide (0.10 mmole) were magneticallystirred in a 250 ml Erlenmeyer flask equipped with a drying tube. Itsolidified after 6-8 hours. On the following day, 100 ml of hexane wasadded and stirring was resumed for four hours. The product was filteredand the residue was washed with solvent. It was dried in vacuum and left24.60 g. The filtrate was evaporated to constate weight on a steam bathand yielded 12.95 g. GC analyses of a hydrolyzed sample of the solid andthe original filtrate gave the following results:

    ______________________________________                                                     Solid                                                            Component    (hydrolyzed) Filtrate                                            ______________________________________                                        m,p-Cresol    .69, 0.73   1.10                                                2,4-2,5-Xylenol                                                                            1.91, 2.03   21.79                                               3,5-Xylenol  97.39, 96.33 59.79 with shoulder                                 3,4-Xylenol group                                                                          --           13.73                                               trimethylphenol                                                                            --           4.03                                                ______________________________________                                    

What is claimed is:
 1. A complex consisting essentially of 3,5-xylenoland calcium bromide.
 2. A complex consisting essentially of 3,4-xylenoland calcium bromide.